Jenny Gunn, Katie Levick guide Diamonds to nerve-jangling win

England star Tammy Beaumont's 70 was in vain as the Northern Diamonds completed a thrilling chase of 200 by one wicket with two balls remaining against Lightning at Durham to close in on the Rachael Heyhoe Flint Trophy knockouts.

Since being left out of England's Commonwealth Games squad last Saturday, opener Beaumont has posted 119, 74 and this 70 off 105 balls in fixtures for England, England A and Lightning.

But she was one of nine wickets to fall for 79 runs as her region slipped from 120 for 1 to 199 all out at the Seat Unique Riverside, handing Diamonds the chance of a fourth straight win to maintain pressure on pre-game leaders and defending champions Southern Vipers.

It was an opportunity they did not pass up, despite significant alarm at 184 for 8 and then 197 for 9. Jenny Gunn finished with 41 not out off 77, while Katie Levick hit the winning through the covers off Marie Kelly's offspin.

Beaumont's former England opening partner Lauren Winfield-Hill fell for 61 having got the chase off to a solid start. But, like the Lightning innings, Diamonds struggled against spin on a slow pitch. Kirstie Gordon, Josie Groves and Lucy Higham (3 for 50) shared seven wickets.

Earlier, New Zealand offie Leigh Kasperek impressed with 3 for 39 from 10 overs for the hosts - all Lightning wickets falling to spin as they lost their third game in four.

In the final game before the near seven-week break for the Commonwealth Games and the Hundred, the Loughborough-based side lost four wickets for one run in nine balls after electing to bat.

They fell from 153 for 2 in the 35th over to 154 for 6 in the 37th on a slow pitch used for Tuesday's men's ODI between England and South Africa. Kelly's run-a-ball 37 included a six over long-off, and she led a 69-run opening partnership in 14 overs with Beaumont.

After she fell to a brilliant diving catch by Gunn off Levick - the legspinner's 150th women's List A wicket in her 101st match - a 51-run stand followed between Beaumont and Sarah Bryce. However, the signs of a home fightback were there.

Diamonds' spinners slowed the rate, racing through their overs and also applying pressure with some tidy fielding and clever field placing from captain Hollie Armitage.

And it worked a treat, as wickets started to fall. The Bryce sisters, Sarah and then Kathryn, both offered up simple catches off Armitage's leg-spin. The latter was the first of the aforementioned four-wicket middle order slump - the fixture's key period.

Kasperek trapped Beaumont lbw sweeping in that collapse. That was the first of two wickets in the 36th over, Bethan Ellis also trapped in front (154 for 6).

Left-armer Linsey Smith, who claimed two wickets to match Armitage and Levick, bowled one over in just 99 seconds. Veteran seamer Gunn bowled another in two minutes, nine seconds. Higham then ensured a target of 200 with an entertaining 27.

Diamonds encountered similar issues in their chase, despite a second-wicket 70 partnership between Winfield-Hill and Armitage. Smith had been trapped lbw by Grace Ballinger's left-arm swing in the second over before the experienced pair settled things down, Armitage contributing 20.

Winfield-Hill lofted Gordon's left-arm spin for an eye-catching six over long-on on the way to a 57-ball 50. But by the time she reached it, Diamonds were 94 for 3 in the 19th over having lost Armitage and Sterre Kalis to Gordon, played on and lbw respectively.

Fledgling allrounder Phoebe Turner chipped a return catch to legspinner Groves, and when Winfield-Hill slog-swept Higham's offspin out to deep midwicket, Lightning believed again at 131 for 5 in the 27th over.

England A wicketkeeper bat Bess Heath sliced Groves to backward point shortly afterwards, further strengthening Lightning's cause. Langston and Kasperek then followed as the equation became 16 needed in eight overs with two wickets remaining.

That became three needed with two-and-a-half overs remaining before ousted Emma Marlow caught at slip. The remaining three runs were secured in singles after Gunn had hit four fours.